1. Field of the Invention
The present invention relates to a location estimation system that can estimate the position of a mobile object both indoors and outdoors.
2. Description of Related Art
Up until the present, in order to obtain the positions of a plurality of mobile objects with good accuracy, various methods have been proposed that employ information relating to the plurality of mobile objects. For example in Japanese Laid-Open Patent Publication 2003-337029 there is proposed a device that calculates the relative positional relationship between one mobile object and another mobile object accurately by utilizing the satellite signals from the per se known GPS (Global Positioning System), and that maps the positions of those mobile objects upon a map by considering their relative positional relationship that has thus been calculated. Furthermore in Japanese Laid-Open Patent Publication 2002-340589 there is described a method in which a base station is installed at a position that is accurately known, an error calculated by subtracting the pseudorange measured at the base station from the pseudorange observed by a GPS terminal is taken as correction information, and, by a VRS information distribution server SS distributing this correction information via a network, the position is corrected on the basis of this correction information that the mobile object receives via the network. And in Japanese Laid-Open Patent Publication 2009-150722 a method is described in which the probability distributions of the positions on Earth of three or more mobile objects are calculated, and thereby the positions of these mobile objects are specified. Moreover in Japanese Laid-Open Patent Publication 2008-312054 a method is described in which the period of a signal is determined using some threshold value, and errors in the detection of GPS signals can be reduced by employing this.